The present invention relates to storage devices for holding large numbers of removable media, more particularly to media magazine latch mechanisms for such storage devices.
In the computer industry many types of devices are used in conjunction with computers for storing and managing data. One such device is a library having large numbers of storage slots for storing removable media. Media generally comprise a magnetic or optical material in the shape of a disk or tape, store computer readable data, and are surrounded by a plastic housing. A library user, generally a robot arm, sometimes called a picker or MTA, inserts and extracts media from the library containers.
To allow the users of libraries easy access to their media, devices in use today have media magazines. A media magazine is a removable container that holds one or more pieces of media so as to allow a user to insert the media into the library or to remove it from the library. To provide access to the media magazine, many libraries in use today have an access door, a latch mechanism, and a solenoid. An access door is a door at the front of the library that must be moved up, down, or aside to provide passage to the media magazine as it is inserted or extracted from the library, thus allowing access to the magazine when opened. Another common element of many libraries is a latch mechanism. Once a media magazine is inserted into the library, it engages a latch mechanism which holds the media magazine in place inside a container. Yet another common element of many libraries is a solenoid unit, including a solenoid coil and a metal plunger. The solenoid coil produces a strong magnetic force when a current is passed through it, which magnetic force manipulates the metal plunger to provide force and motion to the mechanism. Solenoids are often used to release the media magazine free from the latch mechanism so that the media magazine can be removed.
The overall design of conventional latch mechanisms can be very complex. Latch mechanisms used today utilize numerous small mechanical and electronic components, such as electronic sensors or motors. Those many small mechanical and electronic components can easily add significant product costs. A complex design, with many parts and components, also increases the possibility of malfunction and difficulty of repair. Furthermore, a complex design may even require the use of software or advanced timing circuitry.
In addition to complex designs of latch mechanisms, some overall library designs overutilize solenoids in conjunction with the latch mechanism. More specifically, some designs require that a solenoid maintain a current within its coil for prolonged periods of time while waiting for a user to remove a magazine, while other designs utilize more than one solenoid when latching or unlatching the magazine into the library. These prolonged or excessive uses of solenoids increase power consumption and potentially reduce product life.
Yet another disadvantage of current libraries is the lack of protection to internal components provided by a safety door. A safety door can block access to foreign objects, such as dust, as well as providing protection to the user from contact with internal components.
Thus, contemporary libraries utilize unnecessarily complex and expensive latch mechanisms, overutilize solenoids, and provide little to no protection to internal parts beyond the limited function of an access door. Therefore, there exists a need for a library that utilizes a latch mechanism that is simple, efficient, and reliable in design and utilizes fewer costly, power consuming parts or circuitry; that makes limited use of solenoids; and that provides protection to internal parts.
The present invention provides solutions to the disadvantages of current storage devices. A media magazine container, according to the invention, has a recirculating latch mechanism that makes minimal use of a solenoid and includes a safety door. An exemplary embodiment of the latch mechanism includes a contoured latch arm with a configured opening and a shoulder; a slider moving in a slider track and coupled to the latch arm; and a restoring device, such as a spring, for providing a counteractive force. As a magazine is inserted into the container, it encounters the latch arm in a position ready to receive it. The magazine then slides along the contour of the latch arm, forcing it downward and causing the configuration in the latch arm to interact with the slider. The interaction between the slider and configured opening controls the movement of the latch arm, which movement of the latch arm guides the magazine toward the latch arm shoulder. As the magazine moves further into the container, the spring lifts the arm upward keeping the magazine in constant contact with the arm contour, and when the magazine reaches the shoulder in the latch arm, the magazine becomes locked in place. The magazine can be easily unlatched by forcing the latch arm downward causing the slider and configured opening to interact. As the magazine is extracted from the container, the slider and configured opening interact in such a manner that when the magazine is fully extracted, the latch arm is back to the original position where it first received the magazine, and is ready to receive another.
One aspect of the exemplary embodiment includes a detaching means, such as a solenoid or a mechanical lever, to assist in the unlatching of the magazine. The design of the latch mechanism allows the magazine to be extracted by a simple, momentary use of the detaching means which forces the latch arm downward long enough for the magazine to detach from the latch arm shoulder. Interaction between the slider and configured opening prevents the latch arm from locking the magazine in place again. If the detaching means is a solenoid, a momentary use allows for very limited power consumption.
Another aspect of the exemplary embodiment includes a safety door and where the latch mechanism can actuate both the safety door and an access door. The latch mechanism includes a latch arm with an end and a stroke. The end connects to an access door via an access door coupling and the stroke connects to a safety door via a safety door coupling. The design of the latch mechanism actuates the access door and safety door at proper times during insertion and extraction of the magazine, providing security to the internal parts of the container.
The advantages of the present invention will become apparent to those skilled in the art as they consider the following detailed description and its accompanying drawings.